The present invention relates to a glass-ceramic, a process for the production of a glass-ceramic as well as electronic components comprising a dielectric.
There is currently an increasing need for energy storage for times ranging from microseconds to days and a large amount of electrical energy. If the energy stores used in this context are to be quick to charge or discharge, electrical capacitors are often used for this purpose. Capacitors of this type require materials having special dielectric properties. Of particular interest in this context are a high breakdown voltage and, in order to obtain a high storage density, also a high dielectric constant, preferably in combination with a flat temperature profile, in order to make it possible to use the capacitor in a broad temperature range.
In the prior art, polypropylene films are generally used as the dielectric, particularly for high performance capacitors. However, the dielectric breakdown voltage of about 1 V/cm for a dielectric of this type limits the density with which energy can be stored.
In order to increase the storage density electrolytic capacitors, for example, have been proposed. Jeol in Japan has announced a dual-layer electrolytic capacitor having a storage density in the order of magnitude of 20 Wh/l (JP 11288852 A2). However, the electrolytes used as the dielectric in capacitors of this type are generally chemically reactive, and harmful to the environment and, in some cases, can even be explosive.
It is further known to use glasses as the dielectric, e.g. for capacitors. Capacitors which use glass as the dielectric are, however, often complicated to produce and accordingly expensive.
It is furthermore known to use ceramic materials, in particular also Ba—TiO3 ceramics, as the dielectric. In this case, however, the dielectric breakdown voltage of ceramics is limited by their residual porosity.